Power electronic submodule with DC and AC potential connection surfaces

Abstract

Power electronic submodule (2) with a switching device comprising a substrate (4) having a first DC potential conductor (42) with a first DC potential connection surface (426) arranged thereon and a second DC potential conductor (44) with a second DC potential connection surface (446) arranged thereon, wherein the DC potential connection surfaces (426, 446) are preferably arranged directly adjacent to each other, as well as an AC potential conductor (43) and an AC potential connection surface (436) thereon, comprising a plurality of power semiconductor devices (50), comprising an internal connection device (52) which is in the form of a film stack consisting of one or more at least partially structured and alternately arranged electrically insulating and electrically conductive films, and comprising a pressure device (9) comprising a pressure element (92),which has a dimensionally stable pressure body (920) and a plurality of rigid or elastic pressure elements (922) and presses on sections of the connection device (52), wherein the first and second DC potential connection surfaces (426, 446) as well as the AC potential connection surface (436) are designed and provided to be directly, with correct polarity and electrically conductive, connected to external DC or AC potential connection elements (60, 64) not belonging to the submodule (2), whereby the substrate (4) is simultaneously pressed onto a support device (3) in the sections of the DC potential connection surfaces (426, 446) as well as the AC potential connection surface (436), and wherein the pressure element (92) has additional pressure bodies (924).which press on the side of the AC potential connection element (60) and the DC potential connection element (64) facing away from the substrate (4), and which is introduced via a pressure introduction element (90) that not only exerts central pressure on the pressure element (92), but also exerts pressure aligned with the respective connection surfaces (426, 436, 446) of the conductor tracks and the associated DC and AC potential connection elements (60, 64).

Description

[0001] The invention describes a power electronic submodule with a switching device comprising a substrate that has a first DC potential conductor, a second DC potential conductor, and an AC potential conductor, with a plurality of power semiconductor devices and with an internal connection device. The invention further describes such a submodule or a plurality thereof and with a support device for it, which may in particular be designed as a cooling device.

[0002] DE 10 2017 115 883 A1 discloses as prior art a submodule and an arrangement thereof, wherein the submodule comprises a switching device with a substrate and conductive traces arranged thereon. The submodule has a first and a second DC voltage conductive trace and, electrically connected thereto, a first and a second DC voltage connection element, as well as an AC potential conductive trace and, electrically connected thereto, an AC potential connection element. The submodule further comprises an insulating body that encloses the switching device in a frame-like manner. The first DC voltage connection element rests with a first contact section on a first support body of the insulating body, and the AC potential connection element rests with a second contact section on a second support body of the insulating body.A first clamping device is designed to extend electrically insulated through a first recess of the first support body and to form an electrically conductive clamping connection between the first DC voltage connection element and an associated first DC voltage connection element, and a second clamping device is designed to extend electrically insulated through a second recess of the second support body and to form an electrically conductive clamping connection between the AC potential connection element and an associated AC potential connection element.

[0003] DE 10 2016 123 697 A1 discloses as prior art a pressure device for a power electronic switching device, which is designed with a planar, extended rigid base body and an elastically deformable elastomer body, wherein the base body and the elastomer body are connected to each other by force-fit or form-fit and reversibly, and wherein the elastomer body has a plurality of pressure bodies. Furthermore, two power electronic switching devices and an arrangement with such a pressure device are presented.

[0004] DE 10 2007 003 587 A1 discloses as prior art a power semiconductor module in pressure contact configuration with a substrate having power semiconductor components arranged thereon, a housing, externally leading load connection elements, and a pressure device. The substrate has conductor tracks with load potential on its first main surface. The load connection elements are each designed as a metal molded body with a band-like section and contact feet extending from this section. According to the invention, at least one pressure body is arranged between the pressure device and a further load connection element, wherein a part of this pressure body extends through the first load connection element and exerts pressure on a pressure receiving point of the associated further load connection element.

[0005] DE 10 2009 005 915 A1 discloses as prior art a power semiconductor module in pressure contact design, intended for mounting on a cooling component. The power semiconductor module has at least one substrate on which power semiconductor components are arranged. A pressure contact device serves to pressurize the power semiconductor components to the at least one substrate and to dissipate heat from the substrate to the cooling component. The pressure contact device is designed as an active cooling device.

[0006] DE 10 2006 025 531 A1 discloses as prior art a power converter module with power semiconductor chips, each having a first contact surface on one side and a second contact surface and optionally a gate on the opposite second side. The first contact surfaces are each connected to a heat sink. A printed circuit board (PCB) is provided on the second side of the power semiconductor chips, serving to connect the second contact surfaces and the gates. The driver electronics components for the gates are provided on the PCB. The PCB and the power semiconductor chips are pressed against the heat sinks by means of a pressing device to establish the circuit connections.

[0007] In light of the aforementioned prior art, the invention is based on the objective of presenting a power electronic submodule, wherein the respective connections to DC potential connection elements and an AC potential connection element are particularly advantageously designed.

[0008] This problem is solved according to the invention by a power electronic submodule with a switching device having a substrate comprising a first DC potential conductor track with a first DC potential connection surface arranged thereon and a second DC potential conductor track with a second DC potential connection surface arranged thereon, wherein the DC potential connection surfaces are preferably arranged directly adjacent to each other, as well as an AC potential conductor track and an AC potential connection surface thereon, comprising a plurality of power semiconductor devices, comprising an internal connection device comprising a stack of films consisting of one or more at least partially structured and alternately arranged electrically insulating and electrically conductive films, and comprising a pressure device comprising a pressure element.which has a dimensionally stable pressure body and a plurality of rigid or elastic pressure elements, wherein the first and second DC potential connection surfaces as well as the AC potential connection surface are designed and intended to be directly, polarity-correctly and electrically conductively connected to external DC or AC potential connection elements not belonging to the submodule, whereby the substrate is simultaneously pressed onto a support device in the sections of the DC potential connection surfaces as well as the AC potential connection surface and wherein the pressure element has additional pressure bodies which each press on the side of the AC potential connection element as well as the DC potential connection element facing away from the substrate and wherein this pressure is introduced via a pressure introduction element which not only exerts central pressure on the pressure element,but also exerts pressure on the respective connection surfaces of the conductor tracks and the associated DC and AC potential connection elements in alignment with them.

[0009] It is particularly advantageous if an insulating material molded body encloses the switching device in a frame-like manner, at least partially.

[0010] Preferably, the substrate comprises an insulating body or layer on which the first and second DC potential conductors, as well as the AC potential conductor, are bonded together. It is particularly preferred if the insulating body or layer is bonded together on a metal body or layer. This results in a substrate of at least three layers, including a middle insulating layer.

[0011] Preferably, the internal connection device can be designed as bond connections, in particular wire bond connections, or as a stack of foils consisting of one or more electrically insulating and electrically conductive foils that are at least partially structured and arranged alternately.

[0012] The problem is further solved by a power electronic submodule as described above and a support device, which is designed in particular as a cooling device. A first and a second clamping device are each anchored in the support device, wherein the first clamping device forms an electrically conductive, force-fit connection between the AC potential connection surface and the AC potential connection element, and wherein the second clamping device forms an electrically conductive, force-fit connection between the first DC potential connection surface and the first DC potential connection element, and simultaneously between the second DC potential connection surface and the second DC potential connection element.It is therefore essential that the respective connection surfaces for external connections are an integral part of the substrate on which the power semiconductor components are also arranged.

[0013] It can also be advantageous if a number of submodules, preferably with a common overall housing, form a power module.

[0014] Of course, unless this is explicitly excluded per se, the features mentioned in the singular, in particular the respective connecting surfaces, can also be present multiple times in the submodule according to the invention.

[0015] It is understood that the various embodiments of the invention can be implemented individually or in any combination to achieve improvements. In particular, the features mentioned and explained above and below, regardless of whether they are described herein within the context of the submodule or the arrangement, can be used not only in the specified combinations, but also in other combinations or individually, without departing from the scope of the present invention.

[0016] Further explanations of the invention, advantageous details and features, will become apparent from the following description of the invention contained in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8 to Fig. 9 schematically illustrated embodiments of the invention, or of respective parts thereof. Fig. Figure 1 shows a state-of-the-art power electronic submodule. Fig. Figure 2 shows a top view of a submodule to illustrate the invention. Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 shows variants of power electronic submodules, each in a side sectional view. Fig. Figure 7 shows another submodule in top view. Fig. Figure 8 shows a three-dimensional representation of a power electronic submodule. Fig. Figure 9 shows a top view of a submodule for a multi-level power converter.

[0017] Fig. Figure 1 shows a lateral sectional view of a part of an arrangement 1 according to the prior art with a power electronic submodule 2, also according to the prior art. Here, the submodule 2 is arranged on a liquid cooling device 3. This entire arrangement 1 forms a so-called half-bridge circuit.

[0018] The switching device has a substrate 4 with an insulating body 40, designed as a ceramic body, for electrical insulation from the liquid cooling device 3 and for thermal coupling to this liquid cooling device 3. This ceramic body 40 has a plurality of conductive traces 42 on its side facing away from the liquid cooling device 3, which exhibit different potentials during operation of the switching device.

[0019] On at least one of these conductor tracks 42, which together with the insulating body 40 form the substrate 4 of the switching device, power semiconductor components 50 are arranged in a manner typical for the industry and connected in accordance with the circuit requirements. The internal connection device is designed here as a standard foil composite 52 made of alternatingly stacked electrically conductive and electrically insulating foils.

[0020] For external connection, this power converter module 2 has two DC connection elements 680, 682, each of which is electrically connected to one of the DC-carrying DC conductor tracks 42. This connection is standard practice and, here without limitation of generality, is designed as a solder connection.

[0021] These DC potential connection elements 680, 682 serve to connect to associated DC potential connection elements 60, 62, which are preferably connected to a capacitor arrangement.

[0022] In the area of ​​the connection, formed by means of a clamping device 7, between DC potential connection elements 680,682 and DC potential connection elements 60, 62, the first DC potential connection element 680 and the second DC potential connection element 682 form a stack, wherein an insulating device is arranged between the two DC potential connection elements 680,682, although not explicitly shown here.

[0023] The first DC potential connection element 680 rests on a support surface 240 of a housing 20 of the power converter module 2, which is only partially shown. In this configuration, this housing 20 is only designed as a partial housing and therefore does not completely enclose the switching device, as would be possible and customary in the industry.

[0024] The housing 20 of the power converter module 2 is made of a high-temperature-resistant plastic, in this case a polyphenylene sulfide, which also exhibits high flexural stiffness. The DC connection elements 680, 682 are made of thin metal sheets, specifically copper sheets or surface-coated copper sheets, with a thickness of 700 µm. The insulating element between the DC connection elements 680, 682 is made of a plastic with high dielectric strength, in this case an ethylene tetrafluoroethylene copolymer or a liquid crystal polymer, with a thickness of 100 µm.

[0025] In the area of ​​the connection between the DC potential connection elements 680,682 and DC potential connection elements 60, 62, as described, the first DC potential connection element 680 lies on a support surface 240 of the housing 20 and has a recess 684.

[0026] The second DC potential connection element 682 is set back from the first, so that its connection surface to the second DC potential connection element 62 is located on this side of the recess 684 when viewed laterally from the substrate.

[0027] The respective connection surfaces of the DC potential connection elements 680,682 are located on the sides facing away from the cooling device 3, while the respective connection surfaces of the DC potential connection elements 60, 62 are located on the sides facing the cooling device 3.

[0028] The housing 20 has, in the area of ​​its first contact surface 240, a first recess 204 aligned in the z-direction with the recess 684 of the first DC potential connection element 680. An insulating sleeve 74 is arranged in this recess and in the further recesses 684, 620 aligned with it, including that of an AC potential connection element 62. This sleeve serves for the electrical insulation, including any necessary air and creepage distances, of the respective potentials. A screw 70 is arranged in this sleeve 74. Together with a spring assembly 72, which here is designed as a disc spring, it forms the electrically conductive, force-fit connection between the first DC potential connection element 680 and the first DC potential connection element 60, and simultaneously between the second DC potential connection element 682 and the second DC potential connection element 62.For this purpose, the screw 70 is screwed into a blind hole 32 with an internal thread, i.e. a recess of the cooling device 3, whereby the first clamping device 7 is anchored in the cooling device.

[0029] Fig. Figure 2 shows a top view of a submodule 2 to illustrate the invention. The illustration depicts an insulating body 40 of the substrate 4, here a planar ceramic body, preferably and purely by way of example made of aluminum nitride. Excellent alternatives are also aluminum oxide or silicon nitride. Three conductive traces 42, 43, 44 are metallurgically bonded to the ceramic body 40: a first DC conductive trace 42, which carries a first, positive DC potential during operation; a second DC conductive trace 43, which carries a second, negative DC potential during operation; and an AC conductive trace 44, which carries an AC potential during operation.

[0030] Four power semiconductor devices 50, in this case silicon carbide field-effect transistors, are arranged on the first DC conductor track 42 and electrically connected to it. These power semiconductor devices 50 form a first power switch. Alternatively, the power switch can also be formed using silicon-based power semiconductor devices, for example, transistors with antiparallel diodes. These power semiconductor devices 50 are connected to the AC conductor track 43 by means of wire bonds 54, which form the internal connection device. Four identical power semiconductor devices 52 are arranged on this AC conductor track 43 and electrically connected to it. These power semiconductor devices 52 are also connected to the second DC conductor track 44 by means of wire bonds 54.For the sake of clarity, the diagrams of the control conductors for carrying the control potential and connecting them to the power semiconductor components have been omitted here and in the following sections. This diagram represents a standard half-bridge circuit.

[0031] At a first longitudinal end of the substrate 2, an AC potential connection surface 436 is arranged on the AC potential conductor track 43. A first continuous recess 400 extends through this AC potential connection surface 436, the AC potential conductor track 43 and the insulating body 40.

[0032] Also shown are the respective connection surfaces, which are formed from sections of the surfaces of conductor tracks. A first DC connection surface 426 is arranged on the first DC conductor track 42 at a second longitudinal end of the substrate 2. A second DC connection surface 446 is arranged directly adjacent to the first DC connection surface 426 on the second DC conductor track 44 at the second longitudinal end of the substrate 4. A second recess 402, extending through the insulating body 40, is arranged between these DC connection surfaces 426 and 446.

[0033] The first and second recesses 400,402 are arranged on an imaginary mirror line B of the substrate 4, more precisely its insulating body 40.

[0034] Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 shows variants of power electronic submodules 2, in a side sectional view, where the section line of each is analogous to line AA. Fig. 2. This analogy concerns the position of the conductor tracks, the semiconductor components and the recesses; it does not necessarily concern the technical design of the substrate with regard to its materials and structure.

[0035] Fig. Figure 3 shows, partly in exploded view, a part of an arrangement 1, where the substrate 4 in the setup also corresponds to that according to the materials. Fig. 2 corresponds. This substrate 4 is arranged on a liquid cooling device 3, which here forms the support device.

[0036] The same power semiconductor devices 50 are arranged on substrate 4 as under Fig. 2 described. However, the internal connection device here is not designed as wire bond connections, but as a stack 52 of films bonded together in a material-bonded manner. This standard film stack 52 consists here of two electrically conductive films, which may also be structured, and an electrically insulating film arranged between them.

[0037] On the side of the substrate 4 facing away from the water cooling device 3, which also rests on the water cooling device 3 in this area, the AC potential connection surface 436 is arranged and designed as a region of the surface of the AC potential conductor track 43. The entire substrate 4 has the first continuous recess 400 within this surface. The arrangement further includes an AC potential connection element 60, which is not part of the submodule 2. This AC potential connection element 60 serves to connect to an electrical machine, generally designed as an electric motor, which is driven by means of the submodule 2. The AC potential connection element 60 has a continuous recess 600 aligned with the recess 400 of the substrate 4.

[0038] Corresponding to and aligned with these two recesses 400,600, a blind hole 32 with internal thread is arranged in the water cooling device 3, which forms the clamping counter element of a clamping device 7.

[0039] The clamping element of the clamping device 7 is designed as a screw 70, which extends through the recess of the AC connection element 600 and the substrate 400 into the blind hole 32. This design and application of the clamping device 7 presses a contact surface 606 of the AC connection element 60 onto the AC connection surface 436, forming an electrically conductive contact between the AC connection element 60 and the AC conductor track 43. An insulating sleeve 74 is arranged for electrical insulation between the metallic screw 70 and the AC connection element 60 as well as the AC conductor track 43. To improve pressure transmission, a spring element, designed as a disc spring 72 through which the screw 701 extends, is additionally arranged between the screw head and the insulating sleeve 74.

[0040] The clamping device 7 presses the entire substrate 4 onto the liquid cooling device 3, thereby forming the thermal connection between the two. A thermally conductive layer, in particular a thermal paste, can be arranged between the substrate 4 and the liquid cooling device 3, as is customary in the industry.

[0041] Fig. 4 shows one of the Fig. 3. Similar embodiment of arrangement 1, wherein the illustration of a support device has been omitted. The substrate 4 here, however, is designed as a metal body 48, preferably made of aluminum, an insulating layer 41, here designed as an insulating film, arranged thereon in a material-bonded manner, and conductive traces 43, preferably made of aluminum or copper, arranged thereon in a material-bonded manner. All other components and their function are identical to those according to Fig. 3.

[0042] Fig. Figure 5 shows an arrangement 1, wherein the substrate 4 of the submodule 2 is arranged according to that shown in Fig. 3 is formed. The power semiconductor components 50 and the internal connection device 52 are also the same here. In addition, a DC potential connection element is shown, here a first DC potential connection element 60, which carries a negative potential during operation.

[0043] Submodule 2 features a standard pressure device 9, which in turn comprises a pressure element 92 consisting of a dimensionally stable pressure body 920 and a plurality of elastic pressure elements 922. This pressure device 92 is pressurized by means of a pressure induction element 90. The pressure is applied centrally to the pressure device 9 without any general limitation. The pressure elements 922 of the pressure device 9 press against sections of the connection device 52 that are aligned with the power semiconductor components 50. Thus, for a force-fit connection, the substrate 4 is pressed against the liquid cooling device 3 at those points where the most heat is generated.

[0044] The pressure is introduced by means of the pressure introduction element 90, which is effected by two clamping devices 7. These clamping devices serve to provide a positive connection between the AC potential conductor 43 at the AC potential connection surface 436 and the associated connection surface of the AC potential connection element 60, as well as between the first DC potential conductor 42 at the first DC potential connection surface 426 and the associated connection surface of the first DC potential connection element 64. These respective connections are further configured as described above.

[0045] Fig. Figure 6 shows an arrangement 1 with a liquid cooling device 3, a submodule 2 according to the invention arranged thereon, as well as an alternating potential connection element 60 and a first direct potential connection element 64.

[0046] The substrate 4 is formed here with a ceramic insulating body 40 and a metal layer 49, preferably made of aluminum or copper, which is bonded to the insulating body 40 on the side facing the liquid cooling device 3. On the side facing away from the liquid cooling device 3, a plurality of conductor tracks 42, 43 are bonded together. Three power semiconductor devices 50, here silicon carbide field-effect transistors, are shown on the AC conductor track 43. This conductor track has a doubling 438 belonging to the conductor track in the area of ​​the AC connection surface 436 to the AC connection element 60. The first DC conductor track 42 together with the first DC connection surface 426 is also shown.

[0047] Also shown is a printing device 9, which is basically the same as that shown in the Fig. 5 is similar, but has extended functionality. The pressure element 92 has additional pressure bodies 924, each of which presses on the side of the AC potential connection element 60 and the DC potential connection element 64 facing away from the substrate 4. This pressure is initiated via a pressure initiation element 90, which not only exerts central pressure on the pressure element 92, but also, aligned with the respective connection surfaces 426, 436 of the conductor tracks and the associated connection elements, on them.

[0048] The clamping devices themselves are not shown here and are not located in the immediate vicinity of the respective connection surfaces shown.

[0049] Fig. Figure 7 shows another submodule 2 in a top view. This is essentially the same as the one shown in Figure 7. Fig. 2, however, does not have wire bond connections 54 as an internal connecting element. Rather, this substrate 4 has a previously described foil stack 52 as an internal connecting element. This foil stack 52 is, however, only shown with dashed lines and transparently, and thus only indicated. A central, third continuous recess 404 of the substrate 4 is shown, the function of which is related to the following Fig. 8 is described. All continuous recesses 400, 402, 404 are arranged on a line that defines a symmetry axis of the base surface of the substrate 4, i.e., the insulating body 40.

[0050] Fig. Figure 8 shows a three-dimensional representation of a power electronic submodule 2. The substrate 4 is functionally identical to that shown in Figure 8. Fig. 7, however, exhibits geometric deviations at its longitudinal ends. The substrate 4 is almost completely enclosed in a frame-like manner by an insulating material molded body 20, which thus forms a partial housing of the submodule 2.

[0051] Furthermore, submodule 2 has a pressure device 9 with a pressure element 92, which comprises a dimensionally stable pressure body 920 and a plurality of rigid, invisible pressure elements that press against areas of the substrate 4 where no power semiconductor components are arranged. The substrate 4, as already described in Fig. Figure 7 shows a third, centrally arranged, continuous recess which is aligned with a recess of the pressure device. These recesses are designed and intended so that a pressure introduction element 90, which here is designed as a screw with a disc spring, extends through them and presses the substrate 4 onto the support device by means of the pressure device 9.

[0052] Fig. Figure 9 shows a top view of submodule 2 for a multi-level power converter. The first DC conductor 42 is not configured to carry negative potential, but rather neutral potential.

[0053] Three power semiconductor devices 50, themselves designed without restriction of generality as silicon carbide field-effect transistors, are arranged on the second DC potential conductor 44, which carries a positive potential during operation. These power semiconductor devices 50 form the upper power switch of the upper branch in a three-level circuit. Three more power semiconductor devices 50, again silicon carbide field-effect transistors, and a power diode 51 are arranged on another conductor 46. These three silicon carbide field-effect transistors form the lower power switch of the upper branch of the three-level circuit, while the power diode 51 forms the upper diode, which connects the potential between the upper switches to neutral.

[0054] The alternating potential connection surface 436 is basically arranged and designed in the same way as the one according to Fig. 7. The two DC potential connection surfaces 426,446 are also arranged and designed in the same way as those according to Fig. 7. The central recess 404 is also arranged and functionally designed like the one according to Fig. 7.

Claims

[1] Power electronic submodule (2) with a switching device comprising a substrate (4) having a first DC potential conductor (42) with a first DC potential connection surface (426) arranged thereon and a second DC potential conductor (44) with a second DC potential connection surface (446) arranged thereon, wherein the DC potential connection surfaces (426, 446) are preferably arranged directly adjacent to each other, and an AC potential conductor (43) and an AC potential connection surface (436) thereon, comprising a plurality of power semiconductor devices (50), comprising an internal connection device (52) comprising a stack of films consisting of one or more at least partially structured and alternately arranged electrically insulating and electrically conductive films, and comprising a pressure device (9) comprising a pressure element (92),which has a dimensionally stable pressure body (920) and a plurality of rigid or elastic pressure elements (922) and presses on sections of the connection device (52), wherein the first and second DC potential connection surfaces (426, 446) as well as the AC potential connection surface (436) are designed and provided to be directly, with correct polarity and electrically conductive, connected to external DC or AC potential connection elements (60, 64) not belonging to the submodule (2), whereby the substrate (4) is simultaneously pressed onto a support device (3) in the sections of the DC potential connection surfaces (426, 446) as well as the AC potential connection surface (436), and wherein the pressure element (92) has additional pressure bodies (924).which press on the side of the AC potential connection element (60) and the DC potential connection element (64) facing away from the substrate (4), and which is introduced via a pressure introduction element (90) that not only exerts central pressure on the pressure element (92), but also exerts pressure aligned with the respective connection surfaces (426, 436, 446) of the conductor tracks and the associated DC and AC potential connection elements (60, 64). [2] Submodule according to claim 1, wherein an insulating material form body (20) which at least partially encloses the switching device in a frame-like manner. [3] Submodule according to one of the preceding claims, wherein the substrate (4) has an insulating body (40) or an insulating layer (41) on which the first and second DC potential conductor track (42,44) as well as the AC potential conductor track (43) are arranged in a material-bonded manner. [4] Submodule according to claim 3, wherein the insulating body (40) or the insulating layer (41) is arranged in a materially bonded manner on a metal body (48) or a metal layer (49).

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